It is known for self-contained computer workstations to be interconnected by a digital network. One advantage of such a network is that users of individual workstations can communicate with one another over the network, for example by means of a typed note, a data file or a program file transmitted to another user. More recently, users have increasingly requested desktop conferencing, remote presentations and other multimedia applications between networked users. However, multimedia applications require high bandwidth communication links between distributed computing systems with minimal communication delay, maximum throughput, and instantaneous burst communication capability. The requirements of multimedia applications make scheduling the appropriate resources difficult.
IBM Technical Disclosure Bulletin (TDB), number 4b, September, 1991, pp. 416-417, Inter-client Resource Usage in Distributed Client Server Presentation Manager System, discloses a distributed client-server presentation system. In such a system, resources, such as cut and paste clipboard, the keyboard, the mouse, etc., are managed across a number of client systems each connected to a display server. The resources are managed by providing generic server functions, neutral to any specific client policies. The Server provides inter-client resource support by managing named "logical resources". Clients use these to assign global ownership. For example, assuming a client system, a "FOCUS" resource is created and ownership is acquired by client nodes which require a focus window to receive keyboard input events. The Client requests a resource by name and can request exclusive or shared access. Data can also be associated with a logical resource.
Another IBM TDB, Apr. 4, 1989, p. 349, Managing Serial Use Resources in a Distributed Data Processing System Using an Insertion Ring, discloses a technique which insures that users of serial facilities in a distributed data processing system are properly sequenced. U.S. Pat. No. 5,031,089; Dynamic Resource Allocation Scheme for Distributed Heterogeneous Computer Systems; discloses a similar system for a plurality of networked computer nodes to reallocate system resources for optimized job performance. U.S. Pat. No. 4,747,130; Resource Allocation In Distributed Control Systems; discloses a similar scheduling system for a distributed process control system.
U.S. Pat. No. 4,953,159; Audiographics Conferencing Arrangement; discloses a system for allowing conferees to exchange displayed text and/or graphics stored locally in their respective data terminals. The conferees may change the displayed text and/or graphics and such changes are automatically distributed to the other data terminals so that all of the conferees view the same information. U.S. Pat. No. 4,389,720; Distributed Digital Conferencing System; discloses a time division communication system for combining those samples going to a particular station forming a conference with combinations of selected time slot samples into a conference sum unique to the station. However, none of the prior art references provide an effective approach for scheduling and coordinating distributed multimedia resources.